Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by a severe itch and symmetrical rash found on the arms, legs, upper back, or abdomen. The rash can have flat lesions, plaques, or raised bumps and can be pink, red, brown, or black. Individual lesions range in size from 0.5 cm up to 2 cm across.

The itching is extreme and often interferes with sleep.
The affected skin often becomes thickened due to repeated scratching.
PN can occur at any age but is more common in the elderly.
It is more common in African Americans than in other racial groups.

Cause of Prurigo Nodularis

The cause of prurigo nodularis is unknown. The condition has been linked to changes in immune system function and nerve function in the skin, leading to severe itching sensations. The condition can appear by itself or can be linked to other skin diseases or medical conditions, including cancer, diabetes, neurologic conditions, infections, chronic kidney disease, psychiatric conditions, or AIDS.